IntroductionSince the 1960s, NASA has developed polar-orbiting operational
environmental satellites for the National Oceanic and Atmospheric
Administration (NOAA). NOAA-M, the latest NOAA spacecraft, is scheduled
for launch June 24, 2002.

The NOAA satellites carry instruments that observe our Earth and
provide global data for NOAA's operational user requirements including
short-, medium-, and long-range weather forecasts. The operational
system consists of two polar-orbiting satellites. One operates in an
afternoon orbit and the other in a morning orbit with equator crossing
times chosen to maximize the usefulness of the data for a variety of
applications.

The NOAA-M satellite.

These spacecraft monitor the entire Earth, providing atmospheric
measurements of temperature, humidity, ozone and cloud images as they
track weather patterns that affect the global weather and climate. The
satellites send millions of global measurements daily to NOAA's Command
and Data Acquisition stations in Fairbanks, Alaska, and Wallops Island,
Virginia, and to its data processing center in Suitland, Maryland,
adding valuable information to forecasting models, especially for ocean
areas, where conventional groundbased data are lacking.

Currently, NOAA has two operational polar orbiters: NOAA-16, launched
in September 2000, into a 2:00 p.m. local solar time orbit and NOAA-15,
launched in May 1998, into a 7:30 a.m. local solar time orbit. NOAAM
will replace NOAA-15 in a 10:00 a.m. local solar time orbit. The new
10:00 a.m. orbit will allow NOAA-M to carry the same instruments as the
2:00 p.m. satellite (both cross the equator two hours away from noon),
and allows for the generation of the same product suite from each
orbit.

NOAA-M will be renamed NOAA-17 after achieving orbit. The satellites
receive a letter designation while under construction on the ground and
are then renamed with a numerical designation after launch. This is done
because the satellites are built in alphabetical order but are not
necessarily launched in this same order. Therefore, to avoid confusion,
they are numbered upon reaching orbit.